Cost comparison of IP/WDM vs. IP/OTN for European backbone networks

As the demand for Internet-based services grows rapidly, carrier IP networks are becoming more of a crucial social infrastructure. Network operators must target to offer higher speeds, larger capacities and higher reliability while trying to reduce cost of operation, flexible introduction of new services and easy adaptation of legacy low-speed traffic to high-speed networks. In this work we compare two proposed architectures from a cost point of view. These two emerging solutions are IP/WDM and IP/OTN. The former consists of core routers connected directly over point-to-point WDM links, whereas the latter connects the core routers through a reconfigurable optical backbone (OTN) consisting of electro-optical cross-connects (OXCs) interconnected in a mesh WDM network. The main result of our analysis is the quantitative cost difference between IP/OTN and IP/WDM for the coming years and the use of 2.5 Gbps vs. 10 Gbps interfaces. Indeed, IP/OTN leads to significant decrease in network cost through reduction of expensive transit IP router ports and by exploiting more scalable and cheap OXC ports.